Domestic violence is a major problem affecting society. Results from our research show that individuals who are physically abusive to their significant others frequently experience a hyperaroused state at the time of the violent act which is characterized by increased motor activity, heightened autonomic nervous system activity and accompanied by feelings of "being out of control". This hyperaroused state is similar to that which occurs in Post Traumatic Stress Disorder (PTSD). Since PTDS has been associated with changes in noradrenergic function, (1) we postulate that subjects who lose control and are physically violent may also have abnormal noradrenergic function. To test this hypothesis, we designed a study to compare the behavioral and biochemical effects resulting from the administration of the alpha-2 antagonist yohimbine between patients who lose control and are physically violent and comparison subjects.